The Effects of Short-Lasting Anti-Saccade Training in Homonymous Hemianopia with and without Saccadic Adaptation

Abstract

Homonymous Visual Field Defects (HVFD) are common following stroke and can be highly debilitating for visual perception and higher level cognitive functions such as exploring visual scene or reading a text. Rehabilitation using oculomotor compensatory methods with automatic training over a short duration (~15 days) have been shown as efficient as longer voluntary training methods (>1 month). Here, we propose to evaluate and compare the effect of an original HVFD rehabilitation method based on a single 15 min voluntary anti-saccades task (AS) toward the blind hemifield, with automatic sensorimotor adaptation to increase AS amplitude. In order to distinguish between adaptation and training effect, 14 left- or right-HVFD patients were exposed, 1 month apart, to three trainings, two isolated AS task (Delayed-shift and No-shift paradigm), and one combined with AS adaptation (Adaptation paradigm). A quality of life questionnaire (NEI-VFQ 25) and functional measurements (reading speed, visual exploration time in pop-out and serial tasks) as well as oculomotor measurements were assessed before and after each training. We could not demonstrate significant adaptation at the group level, but we identified a group of nine adapted patients. While AS training itself proved to demonstrate significant functional improvements in the overall patient group, we could also demonstrate in the sub-group of adapted patients and specifically following the adaptation training, an increase of saccade amplitude during the reading task (left-HVFD patients) and the Serial exploration task, and improvement of the visual quality of life. We conclude that short-lasting AS training combined with adaptation could be implemented in rehabilitation methods of cognitive dysfunctions following HVFD. Indeed, both voluntary and automatic processes have shown interesting effects on the control of visually guided saccades in different cognitive tasks.

Adaptation, perceptual learning, and plasticity of brain functions

“…A systematic review on multisensory stimulation did not allow a valid conclusion about the effectiveness of this intervention [ 24 ]. Another interesting approach was reported using anti-saccadic training [ 25 ].…”

“…Only few RCTs are available: It has been shown that reading scrolled text for right hemianopia was effective to improve reading speed [ 26 ]. Furthermore, reading speed increased by performing a search task in a line of words [ 22 ] and anti-saccade training [ 25 ]. Other approaches, based on clinical experience, are to help orientation on the page by use of visual and tactile aids, for example the index finger, a ruler or a slightly vertically magnifying ruler with a red guideline.…”

Biomechanical adaptation to post-stroke visual field loss: a systematic review

“…In particular AV stimulation significantly increased the number (56 AV and 37 VT) and amplitude of saccades (52° AV and 44° VT). Lévy-Bencheton et al (2015) [ 54 ] Before and after study n = 14 HH (8 right, 6 left) Ischemic stroke Adults The training consisted of three different anti-saccades (AS) training: one with (adaptation) and two without (delayed shift and no shift) saccadic adaptation. Each training lasted around 15–20 min Eye movements were recorded before and after training Eye movements Mean horizontal saccadic amplitude, mean fixation duration.…”

“…Eye movements were recorded using an infrared eye tracking in 16 studies [ 26 , 43 , 44 , 46 , 47 , 49 – 52 , 54 , 55 , 59 – 62 , 64 ]. In two studies, subjects’ eye movements were recorded using a scleral search coil system [ 56 , 57 ].…”

Adaptation to poststroke visual field loss: A systematic review

“…The majority of studies relating to compensatory treatments are concerned with the improvement of eye movements and scanning into the affected field (Bergsma et al., 2011; Roth et al., 2009; Aimola et al., 2014; Hazelton, Pollock, Walsh, & Brady, 2015; Jacquin‐Courtois, Bays, Salemme, Leff, & Husain, 2013; Lane, Smith, Ellison, & Schenk, 2010; Pambakian, Mannan, Hodgson, & Kennard, 2004; Kerkhoff, Münssinger, & Meier, 1994; Mazer et al., 2003; Nelles et al., 2010; Taylor, Poland, Harrison, & Stephenson, 2011; Schuett, Heywood, Kentridge, Dauner, & Zihl, 2012), as well as increased saccadic movements into the affected field (Mannan, Pambakian, & Kennard, 2010; Lévy‐Bencheton et al., 2016; Kerkhoff, Münßinger, Eberle‐strauss, & Stögerer, 1992). A number of studies have specifically reported on subjective improvements in activities of daily living following compensatory therapy, such as improvements in mobility, reading, driving, and detection of obstacles (Bergsma et al., 2011; Ong et al., 2015; Keller & Lefin‐Rank, 2010; Aimola et al., 2014; Jacquin‐Courtois et al., 2013; Kerkhoff et al., 1994; Mazer et al., 2003; de Haan, Melis‐Dankers, Brouwer, Tucha, & Heutink, 2015; Hayes, Chen, Clarke, & Thompson, 2012; Nelles et al., 2001; Rowe, Conroy, et al., 2016).…”